Friday, May 15, 2009

One of the challenges of creating artificial organs for replacement of human body parts is the need for a structural matrix to build the functional tissue around. Australian and Korean scientists have developed an interesting approach to the problem by pairing carbon nanotubes and DNA strands together, then treating them with calcium chloride solution to create cross-linking between the fibres.

The new concept uses DNA strands as a matrix; the strands completely “wrap” the scaffold-forming carbon nanotubes in the presence of an ionic liquid, networking them to form a gel. This gel can be spun: just as silk and synthetic fibers can be wet-spun for textiles, the gel can be made into very fine threads when injected into a special bath. The dried fibers have a porous, sponge-like structure and consist of a network of intertwined 50 nm-wide nanofibers. Soaking in a calcium chloride solution further cross-links the DNA, causing the fibers to become denser and more strongly connected.

These spongy fibers resemble the collagen fiber networks of the biological extracellular matrix. They can also be knotted, braided, or woven into textile-like structures. This results in materials that are as elastic as the softest natural tissues while simultaneously deriving great strength from the robust DNA links. An additional advantage is the electrical conductivity of the new material, which can thus also be used in electrodes for mechanical actuators, energy storage, and sensors. _Wiley

A similar matrix might be seeded with living cells to create tendons, cartilage, or more complex structures such as noses, ears, blood vessels, eyelids, lips, or as support reinforcement for hernia or breast surgeries etc. Reconstructive surgery and vascular surgery would create a demand for such living replacement parts immediately, should they prove safe and durable.

For more complex organs such as kidneys, livers, lungs, and hearts, more breakthroughs will be needed. For intermediate structures such as bladders, rectums, and other GI or GU segments, the jump from simple replacement parts may not be too difficult once the best ways for making the simpler parts are perfected.